Honing apparatus

ABSTRACT

A honing apparatus for super finishing the bore surface of a machine part and particularly the epitrochoidal bore surface of the stator part of a Wankel engine. The apparatus includes mounting structure for mounting three honing stones internally of the stator for movement in the same manner as the rotor of the Wankel engine. The apparatus further includes control mechanism for moving the honing stones into and out of contact with the bore surface of the stator.

United States Patent 1 Hoglund HONING APPARATUS [75] Inventor: Nils O.Hoglund, Short Hills, NJ.

[73] Assignee: Tri-Ordinate Corporation, Berkeley Heights, NJ.

221 Filed: Jan. 26, 1972 [21] Appl. No.2 220,772

[52] US. Cl 51/90, 51/346, 51/349 [51] Int. Cl B24b 5/16, B24d 5/06 [58]Field of Search 51/90, 43, 34 H, 51/34 J, 349, 338, 346, 165.9, 165.93,245,

[56] References Cited UNITED STATES PATENTS 3,466,809 9/1969 Estabrook51/34 R X FOREIGN PATENTS OR APPLICATIONS 652,022 10/1937 Germany 51/349Nov. 27, 1973 957,922 5/1964 Great Britain 51/90 Primary ExaminerDonaldG. Kelly Attorney-Dean S. Edmonds et a1.

[5 7] ABSTRACT 6 Claims, 6 Drawing Figures Patented Nov. 27, 1973 4Sheets-Sheet 1 Patented Nov.

FIG. 2

4 Sheets-Sheet 2 Patented Nov. 27, 1973 3,774,346

4 sheets-sheet :5

Patented Nov. 27, 1973 4 Sheets-Sheet 4 I. llllll G am P FIG. 6

1 HQNING APPARATUS BACKGROUND OF THE INVENTION In the construction ofthe stator part of a Wankel engine, the internal bore is formed to anepitrochoidal shape. The final formation of this shape is usually doneby a grinding operation after which the stator is ready for use in theWankel engine. If the grinding operation does not provide a completelyuniform surface, the use of the stator without further surface finishingof the bore may produce improper engagement between it and the rotorpart of the engine. Where the grinding operation does not provide anacceptable surface finish, subsequent polishing is necessary. Usually,this polishing, if done at all, is done by hand which, of course, is atime-consuming and expensive operation.

SUMMARY OF THE INVENTION In accordance with the teachings of the presentinvention, applicant has developed a honing apparatus particularlysuited for polishing the internal epitrochoidal bore surface of thestator of a Wankel engine. This honing apparatus can be mostadvantageously used where the prior grinding of the bore surface has notformed an acceptably uniform surface finish. Also, even where the priorgrinding has produced an extremely accurate and uniform surface,subsequent polishing with the honing apparatus of the present inventionmay be desirable.

In construction, the honing apparatus generally includes a rotor housingrotatably positioned within the bore of the stator for movement inprecisely the same manner as the rotor of the Wankel engine will moveinside this stator. Fixed to the rotor housing are three honing stones.These stones are spaced from each other and located in contact with theinternal bore surface of the stator in the same manner as the threesealing members which are included on the rotor of a Wankel engine. Withthe above construction, the honing stones will follow a path identicalto that normally followed by the rotor of the Wankel engine. Thus, thecomplicated epitrochoidal shaped surface of the bore of the stator willbe accurately followed by the honing stones to produce accuratepolishing of this surface.

With applicant's honing apparatus, control means are provided foradjusting the position of the honing stones within the bore of thestator workpiece being honed. This control means is used to move thehoning stones under some degree of pressure against the internal boresurface and to hold it in this position during the honing operation. Thecontrol means is also operable to move the honing stones away from thesurface being honed to permit removal of the honing apparatus from thefinished stator workpiece and to permit entry of the next workpiece tobe honed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 5 is a side view of the foottreadle mechanism used for controlling the honing operation; and

FIG. 6 is a side view partialy in cross-section of an alternativeembodiment of the honing apparatus of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIGS. 1 and 2, thehoning apparatus generally includes an upright support structure 1 forslidably holding the honing mechanism 2 for vertical movement inoverlying alignment with a workpiece 3 such as the stator part of aWankel engine. The workpiece is, in turn, mounted on support meansgenerally designated at 4. The lower end of the honing mechanismincludes a honing rotor housing 5, most clearly shown in FIG. 3, towhich are secured three honing members 6 for engaging against theinternal bore surface 7 of the stator workpiece. As shown, this surface7 defines an epitrochoid.

In order to permit entry of the rotor housing and honing members intothe bore of the stator workpiece, the honing mechanism 2 is slidablymounted on the support structure 1 by way of the dovetailed connection 8shown in FIG. 4. Sliding movement of the honing mechanism is effected byactuation of a hydraulic power cylinder 9 mounted on the supportstructure 1 by a bracket 10. The piston rod 11 of the power cylinder isconnected by a bracket 12 to a slide support structure 13 in which adovetailed slot is cut for the connection 8.v Extension and retractionof the piston rod of the hydraulic power cylinder will cause loweringand vraising of the honing mechanism into and ou't of operativeassociation with the stator workpiece to be honed.

For rotating the rotor housing within the bore of the stator workpiece,an internal gear 14 is fixed to the upper surface of the rotor housingin meshing engagement with a stationary gear 15 fixed to the slidesupport structure 13. The internal gear 14 has a 3:2 gear ratio with thefixed gear 15 which is located concentrically relative to the centralaxis 3 of the stator workpiece. A drive shaft 16 extends perpendicularto the plane in which the workpiece lies and coaxially through thestationary gear 15. At its lower end, the drive shaft is connected tothe rotor housing to effect rotation thereof as more fully describedbelow. A sleeve bearing 17 is secured in the bore of the stationary gearfor rotatably supporting the drive shaft at its lower end. A secondsleeve bearing 18 is secured to the slide support structure 13 forrotatably supporting the drive shaft at its upper end. The drive shaftis supported against axial downward movement in the slide supportstructure by a thrust bearing 19 and lock nut 20.

The lower end of the drive shaft is constructed as an eccentric crank21. The outer peripheral surface of the crank is circular and isreceived within a bore 22 of the rotor housing located centrally of thehousing. The central axis of the rotor housing is shown at 22' in FIGS.2 and 3. A retaining plug 23 is secured to the lower end of the crank 21by screws such as shown at 24, to retain the shaft against lifting outof the rotor housing 5. A thrust bearing 25 provides a bearing supportbetween the housing and the retaining plug. To facilitate relativerotation of the crank 21 in the bore 22 of the rotor housing a sleevebearing 26 is fixed to the rotor housmg.

At the upper end of the drive shaft, a pulley 27 is attached forreceiving therearound a drive belt 28. The drive belt is run around asecond pulley 29 connected to the drive shaft of a drive motor 30.Rotation of the drive shaft will, through the connection of the crank 21with the rotor housing, provide a drive for rotating the rotor housingwithin the bore of the stator workpiece.

With the eccentric connection of the drive shaft to the rotor housingand the gear construction 14, 15, the rotor housing will be restrainedto move in precisely the same manner as the rotor part of the Wankelengine will move within the stator when these two parts are assembledinto a motor.

In order to produce a proper honing of the interior bore surface of thestator workpiece, the honing members are adjustably mounted on the rotorhousing. As shown in FIGS. 2 and 3, each of the members 6 includes ahoning stone 31 for engaging the interior surface of the stator. Thesehoning stones are constructed with a honing surface having the sameradius of curvature as the sealing members of the rotor part of theWankel engine. Holder means, comprised of two parts 32 and 33 pivotallyconnected to each other by a pin 34, are provided for holding the honingstones in a fully supported manner. As shown in FIG. 3, there are threehoning members mounted about the periphery of the rotor housing. Thesemembers are spaced equally from each other about the center 22 of therotor housing with the honing stones 3] located in precisely the samerelative location as the sealing members of the rotor of a Wankelengine. The pivoting action of the two part holder for the stonespermits them to properly engage the straight surface of the statorworkpiece. The axis of pivoting extends perpendicular to the axis of thedrive shaft and also perpendicular to the plane extending through thehoning stone and the center about which all three honing members arepositioned.

The holder means for each of the honing stones is slidably mounted onsupport means 35 through a key connection shown in FIG. 3. The engagingsurfaces of the holder means and support means are inclined so that asthe holder means is moved along the support means, the honing memberswill move radially toward and away from the interior bore surface of thestator workpiece. This radial movement is effected by raising andlowering the holder means and through the key connection of the part 33to the support means 35.

For effecting radial adjustment of the position of the honing members, acontrol means is incorporated into the honing structure with a partthereof located remotely for actuation by the operator of the apparatus.This control means is operatively connected through the drive shaft toeach of the honing members. In construction, it includes a control shaft36 extending longitudinally through the drive shaft with one end 36extending into the rotor housing and into a bore 37 formed in the crank21. The longitudinal axis of the end 36' is coincident with the centralaxis 22' of the rotor housing. As shown in FIG. 2 the offset end 36 ofthe control shaft extends through the retaining plugs 23.

Disposed below the control shaft and in axial alignment therewith is acircular plate member 38. Along the periphery of this plate member,three connecting arms 39 are provided for connecting the plate to eachof the parts 33 of the holder means. Only one of these connecting armsis shown in FIG. 2 and it is to be understood that identical structureis provided for each of the other two honing members. Each of the arms39 is L-shaped in configuration with a section 39' overlying the holderpart 33 with which it is associated. A shoulder screw 40 is connected tothe part 33 and extends loosely through an opening 41 in the arm section39'. The plate 38 together with the arms 39, are mounted within therotor housing for vertical sliding movement in a direction parallel tothe axis of the drive shaft. Spring means 42 are provided for normallyurging the parts 38, 39 upwardly; and due to the connection of thesection 39' to the holder part 33 such upward movement will cause thehoning stone holders to move upwardly along their inclined supportsurface and radially inwardly away from the interior surface of thestator workpiece.

To effect radial outward movement of the honing stones, the controlshaft 36 is pushed axially downwardly to move the plate 36 andconnecting arms 39 against the force of the springs 42. This axialmovement of the control shaft is produced by actuation of a foot treadlemechanism connected through linkages to the upper end of the controlshaft.

As shown in FIG. 2, a bearing retainer member 43 is fixed to the upperend of the control shaft for holding a thrust bearing 44 through which aplug member 45 extends. The upper surface of the plug member is engagedby a plunger 46 mounted on one end of a control lever 47. The controllever 47 is pivotally mounted intermediate its ends at 48 on a bracket49 fixed to the slide structure 13. The other end of the control lever47 has secured thereto a pusher rod 50. This pusher rod extendsdownwardly into a hollow rod the lowerend of which is, as shown in FIG.5, attached to one end of a foot treadle 52. The foot treadle 52 is, inturn, pivotally mounted at 53 so that depressing of its free end 54 willcause an upward movement of the hollow rod 51. This will continue untilthe upper end of the rod 51 contacts a collar member 55 secured to therod 50. Further upward movement will cause the rod 50 to move upwardlyand this will, in turn, cause the lever 47 to pivot about the axis 48and press the plunger 46 downwardly against the plug 45 of the controlshaft. The sliding connection of the pusher rod 50 within the hollow rod5] permits raising of the entire honing mechanism during changing of theworkpieces.

The extent to which the control shaft is pushed downwardly is controlledby the setting of a micrometer head 56 and a stop member 57. The leverwill pivot counterclockwise about the axis 48 until it engages the stopmember 57. The extent to which this pivoting movement has moved thecontrol rod downwardly can be adjusted by adjusting the micrometer head56 to, in turn, adjust the axial location of the plunger 46. Anindicator 58 is associated with the micrometer head 56 for showing theoperator the setting to which the head has been adjusted.

With the control shaft being pressed downwardly, its lower end 36' willengage and press the plate 38 downwardly against the force of thesprings 42. The axis of the lower end 36' of the control shaft iscoaxial with the center of the rotor housing and it engages the plate 38at its center. Thus, the pressure applied to the plate will bedistributed equally across the plate and cause a balanced movement ofeach of the honing members into pressure contact with the interiorsurface of the stator workpiece. Also, the engagement of the end 36'with the center of the plate will permit a single point of contactbetween these two members as the drive shaft is rotated and itseccentric crank end rotates within the bore of the rotor housing.

ln positioning the honing apparatus within the bore of the statorworkpiece, it is essential that it be located in precisely the same wayas the rotor of the Wankel engine. In order to facilitate this and tocompensate for any misalignment relative to the workpiece, the workpieceis mounted on support structure which is free to float in two directionsextending at right angles to each other. In particular, the support 4comprises a first slide 59 supported on ball bushings by way of two rods61 connected to the undersurface of the slide 59. This constructionpermits movement of the slide 59 to the right and left as viewed in FIG.2. The bushings 60 are themselves mounted on a second slide 62, theundersurface of which is clamped to bushings 63. Each pair of thesebushings is, in turn, slidably on a rod 64 secured to the primarysupport 65 for the entire apparatus. This second bearing support permitsmovement of the honing apparatus in a path perpendicular to the firstsliding movement provided by the first mentioned rod and bushingconnection. The maximum degree of movement necessary to compensate formisalignment and to assure accurate positioning of the honing apparatuswithin the bore of the stator workpiece need be no more than 0.015 inch.

FIGS. 1-5 show the preferred embodiment of the present invention whereinmechanical control means are used for adjusting the positioning of thehoning members. As an alternative embodiment of the invention, pneumaticor hydraulic means may be used for this purpose. Such a construction isshown in FIG. 6 where like reference numerals followed by the sufficprime are used for designating like parts. Here, each of the honingmembers is pivotally mounted on the end of a piston rod 66 of ahydraulic power cylinder assembly. One assembly is provided for each ofthe honing members and positioned in spaced relation about the rotorhousing 5 in the same manner as the support means for the honing membersused in the embodiment of the invention shown in FIGS. 1-6. A source offluid pressure 68 disposed externally of the honing mecha-- nism isconnected to each of the power cylinder assemblies 67 by way of aconduit 69 extending through the drive shaft 16 and into the crank end21'. One or more branch conduits 70 connect conduit 69 to a channel 71formed in the periphery of the crank 21. This channel is located incommunication with an inlet to each of the power cylinder assemblies 67.Seals 72 are provided on the periphery of the crank 21' to preventescape of fluid pressure from the bore of the rotor housing in which thecrank is rotatably positioned.

Applying pressure to the cylinder will cause the honing members to moveradially outwardly into pressure contact with the interior bore surface7 of the stator workpiece 3. When it is desired to retract the honingmembers to permit raising of the rotor housing out of the workpiece andinsertion into a new workpiece, the pressure to the cylinder assembliesis removed. Springs 73 will then take over and move the honing membersto retracted positions. The spring 73 associated with each of the honingmembers is mounted in the rotor housing with one end engaging againstthe housing and the other end engaging against a stud 74 connected tothe honing members. The force of the spring normally urges the honingmembers into retracted position.

I claim:

1. A honing apparatus for honing the interior bore surface of a statormember in which a rotor member is to rotate in a predetermined mannerwith three equally spaced points on the rotor making continuousengagement with said surface, said apparatus comprising:

a. support means for supporting said stator member in a predeterminedplane;

b. a honing rotor housing positionable within the bore of said statormember;

0. means for supporting said housing in the bore of said stator memberfor rotation in said plane;

d. three honing members mounted on said housing at equally spaced pointsabout a central common axis in the same manner as the three points onsaid rotor member for engagement with the interior bore surface of saidstator member, each of the honing members comprising:

1. a honing stone for engaging the interior surface of said stator, and

2. holder means for the honing stone;

e. support means for mounting said honing stones for radial movementtoward and away from the interior bore surface of the stator member,said support means including a supporting surface inclined relative tothe radial movement of the honing stones for engaging the holder meansfor movement therealong to effect said radial movement of the honingstones;

f. drive means for rotating said rotor housing in the same predeterminedmanner as said rotor member is to rotate to move said honing membersalong the interior bore surface of the stator while in continuousengagement therewith, including:

1. a drive shaft connected to said rotor housing, ex-

tending perpendicular to said plane, and into said rotor housing inrotatable relation therewith at a point offset from the center aboutwhich the three honing members are mounted, and

2. power means for rotating said drive shaft; and

g. control means for adjusting the radial location of said honingmembers, said control means being partially disposed externally of saiddrive means and operativelyconnected through said drive shaft to thesupport means mounting the honing members, including:

1. a control shaft mounted for axial movement within said drive shaftwith one end extending into said rotor housing and aligned with thecenter about which the three honing members are mounted,

2. a first part connected to the other end of said control shaft formoving the control shaft axially within said drive shaft,

3. a second part defined by a single plate mounted in said rotor housingin axial alignment with the one end of said control shaft for movementin response to axial movement of said control shaft, and

4. a' third part mounted in said rotor housing for movement in adirection parallel to the axis of said drive shaft and comprising threearms, each of which is connected at one end to said plate and at itsother end to one of the support means for the honing members.

2. A honing apparatus according to claim 1 further comprising:

a. a fixed gear having external teeth mounted consaid plate.

centrically to said drive shaft; 4. A honing apparatus according toclaim 2 further b. an internal gear fixed to said rotor housing and disii Posed in meshmg, Surrounding relation with Said a. means for mountingthe support means for the stafixed gear and tor workpiece for movementin said plane in two c. crank means fixed to the one end of said driveshaft directions perpendicular to each Omen and dlsposefd rotot housmgcrank 5. A honing apparatus according to claim 2 further means having acircular periphery rotatably reincluding:

ceived within a complementary shaped circular bore in said rotorhousing, said bore having a cen- 10 tral axis parallel to and offsetfrom the longitudinal axis of said drive shaft. 3. A honing apparatusfor honing the interior epitrochoidal bore surface of a stator memberaccording to a. spring means for urging said honing members radisaidstator workpiece. 6. A honing apparatus according to claim 5 wherein: a.the first part of said control means comprises:

1. a pivotally mounted lever having one end overlyclaim 2 wherein:

a. the gear ratio between the internal and fixed gears mg h other end ofSam control Shaft extenorly is 32; of sald drive shaft, b. the center ofthe circular bore of the rotor housing a P rod Connected to the otherend of Said coincides with the center about which the three and honingmembers ar mo nt d; nd 20 3. foot treadle means connected to the otherend 0. the control shaft has an offset end aligned with the of said pushrod for controlling movement center of said bore and extending throughthe thereof.

crank means and into contact with the center of ally inwardly away fromthe interior bore surface of

1. A honing apparatus for honing the interior bore surface of a statormember in which a rotor member is to rotate in a predetermined mannerwith three equally spaced points on the rotor making continuousengagement with said surface, said apparatus comprising: a. supportmeans for supporting said stator member in a predetermined plane; b. ahoning rotor housing positionable within the bore of said stator member;c. means for supporting said housing in the bore of said stator memberfor rotation in said plane; d. three honing members mounted on saidhousing at equally spaced points about a central common axis in the samemanner as the three points on said rotor member for engagement with theinterior bore surface of said stator member, each of the honing memberscomprising:
 1. a honing stone for engaging the interior surface of saidstator, and
 2. holder means for the honing stone; e. support means formounting said honing stones for radial movement toward and away from theinterior bore surface of the stator member, said support means includinga supporting surface inclined relative to the radial movement of thehoning stones for engaging the holder means for movement therealong toeffect said radial movement of the honing stones; f. drive means forrotating said rotor housing in the same predetermined manner as saidrotor member is to rotate to move said honing members along the interiorbore surface of the stator while in continuous engagement therewith,including:
 1. a drive shaft connected to said rotor housing, extendingperpendicular to said plane, and into said rotor housing in rotatablerelation therewith at a point offset from the center about which thethree honing members are mounted, and
 2. power means for rotating saiddrive shaft; and g. control means for adjustinG the radial location ofsaid honing members, said control means being partially disposedexternally of said drive means and operatively connected through saiddrive shaft to the support means mounting the honing members,including:
 1. a control shaft mounted for axial movement within saiddrive shaft with one end extending into said rotor housing and alignedwith the center about which the three honing members are mounted,
 2. afirst part connected to the other end of said control shaft for movingthe control shaft axially within said drive shaft,
 3. a second partdefined by a single plate mounted in said rotor housing in axialalignment with the one end of said control shaft for movement inresponse to axial movement of said control shaft, and
 4. a third partmounted in said rotor housing for movement in a direction parallel tothe axis of said drive shaft and comprising three arms, each of which isconnected at one end to said plate and at its other end to one of thesupport means for the honing members.
 2. a first part connected to theother end of said control shaft for moving the control shaft axiallywithin said drive shaft,
 2. power means for rotating said drive shaft;and g. control means for adjustinG the radial location of said honingmembers, said control means being partially disposed externally of saiddrive means and operatively connected through said drive shaft to thesupport means mounting the honing members, including:
 2. holder meansfor the honing stone; e. support means for mounting said honing stonesfor radial movement toward and away from the interior bore surface ofthe stator member, said support means including a supporting surfaceinclined relative to the radial movement of the honing stones forengaging the holder means for movement therealong to effect said radialmovement of the honing stones; f. drive means for rotating said rotorhousing in the same predetermined manner as said rotor member is torotate to move said honing members along the interior bore surface ofthe stator while in continuous engagement therewith, including:
 2. Ahoning apparatus according to claim 1 further comprising: a. a fixedgear having external teeth mounted concentrically to said drive shaft;b. an internal gear fixed to said rotor housing and disposed in meshing,surrounding relation with said fixed gear, and c. crank means fixed tothe one end of said drive shaft and disposed within said rotor housing,said crank means having a circular periphery rotatably received within acomplementary shaped circular bore in said rotor housing, said borehaving a central axis parallel to and offset from the longitudinal axisof said drive shaft.
 2. a push rod connected to the other end of saidlever, and
 3. foot treadle means connected to the other end of said pushrod for controlling movement thereof.
 3. a second part defined by asingle plate mounted in said rotor housing in axial alignment with theone end of said control shaft for movement in response to axial movementof said control shaft, and
 3. A honing apparatus for honing the interiorepitrochoidal bore surface of a stator member according to claim 2wherein: a. the gear ratio between the internal and fixed gears is 3:2;b. the center of the circular bore of the rotor housing coincides withthe center about which the three honing members are mounted; and c. thecontrol shaft has an offset end aligned with the center of said bore andextending through the crank means and into contact with the center ofsaid plate.
 4. A honing apparatus according to claim 2 furthercomprising: a. means for mounting the support means for the statorworkpiece for movement in said plane in two directions, perpendicular toeach other.
 4. a third part mounted in said rotor housing for movementin a direction parallel to the axis of said drive shaft and comprisingthree arms, each of which is connected at one end to said plate and atits other end to one of the support means for the honing members.
 5. Ahoning apparatus according to claim 2 further including: a. spring meansfor urging said honing members radially inwardly away from the interiorbore surface of said stator workpiece.
 6. A honing apparatus accordingto claim 5 wherein: a. the first part of said control means comprises: